1. Field of the Invention
The present invention relates to an electrical connector configured to secure a signal transmission medium by moving an actuator.
2. Description of the Related Art
Commonly, various electrical connectors are widely used as a means of electrically connecting various signal transmission media such as flexible printed circuit (FPC) or flexible flat cables (FFC) in various electrical devices and the like. An electrical connector disclosed in Patent Document 1 and others listed below, for example, which is used as mounted on a printed wiring board, is configured to receive a signal transmission medium such as FPC or FFC inserted thereinto from an opening at the front end of an insulating housing (insulator). An actuator (connection operator) is held in an “open position” where it releases the signal transmission medium when the medium is inserted therein. The actuator is pivoted by a force exerted by an operator toward a “closed position” on the front or the back of the connector, for example by being pushed down.
When the actuator (connection operator) is pivoted to the “closed position” where it sandwiches the signal transmission medium, a cam part provided to the actuator presses one end of conductive contacts, whereby the other end of the conductive contacts is moved to make pressure contact with the signal transmission medium (such as FPC or FFC) to securely hold the same. When the actuator in this “closed position” is pivoted back to the original “open position” by, for example, being pulled up, the conductive contacts move by their own resilient restorative force to separate from the signal transmission medium (such as FPC or FFC), so that the signal transmission medium is released.
The cam part that causes the resilient movement of the conductive contacts is formed by a component having a substantially elliptical cross-sectional shape. It is configured to be rotatably accommodated in cam rotation recesses formed in stationary beams of the conductive contacts, and rotated between the stationary beams and movable beams with changing diameter. Corresponding to this cam part, the movable beams have a cam lock protrusion at one end to face the cam part in a direction in which the signal transmission medium is inserted, so that when the cam part attempts to come out of the cam rotation recesses because of an external force applied to the actuator, part of the cam part abuts on the cam lock protrusions, so that it is locked and does not come out of the connector.
However, the contact pressure of the cam part on the conductive contacts is small when the actuator is in the “open position”, in particular, as the cam part having a substantially elliptical cross-sectional shape lies on its side, because of which the cam rotation recesses hold the cam part less firmly, and also, the cam lock protrusions lock the cam part less reliably. As a result, as shown in FIG. 12, for example, even a small external force applied to the actuator 1 can cause the cam part 4 to move over the steps 3 that form the cam rotation recesses 2 outward of the connector (rightward in FIG. 12), and to be released to the outside of the connector, despite the locking action of the cam lock protrusions 6 provided at one end of the conductive contacts 5.